The long-term goal of the study is to further elucidate the genetic basis of aortic aneurysms (AA). One objective is to determine the prevalence of familial thoracic AA, and the mode of inheritance of these aneurysms. A second objective is to determine the incidence of asymptomatic thoracic AA in first-degree relatives of aortic aneurysm patients who do not have a family history. Another objective is to determine if mutations in the FBN1 or COL3A1 genes are responsible for some of these familial aortic aneurysms.